File Sharing Glossary
26 file-sharing terms explained in plain English - From share links to end-to-end encryption.
- AirDrop
- AirDrop is Apple's built-in feature for sending files directly between nearby iPhones, iPads, and Macs. It uses Bluetooth to discover devices and a direct Wi-Fi connection to move the data, so it needs no internet and costs nothing to use. Between two Apple devices it is fast and keeps full quality, which makes it the default choice for Apple-only households. The catch is that it stops at the edge of Apple's ecosystem: there is no AirDrop for Windows or Android. That matters when you share files across platforms - A photo going from an iPhone to a Windows PC needs a different route, such as a browser-based share link that works on any device.
- Attachment size limit
- An attachment size limit is the largest file a service like email will let you send in one message. Gmail and Outlook cap attachments around 20-25 MB, and chat apps often compress or refuse large files too. Hit the cap and your message bounces or the file arrives squashed. This limit is the single most common reason people switch from attaching to linking: instead of stuffing the file into the message, you upload it once and send a short share link. The link weighs a few bytes, so it never bounces, and the file can be far larger than any inbox allows - On ShareIt.onl, up to 200 MB per share.
- Bandwidth
- Bandwidth is the maximum amount of data a network connection can carry in a set time, usually measured in megabits per second (Mbps). Think of it as the width of a pipe: a wider pipe moves more data at once. Higher bandwidth means files upload and download faster; low bandwidth is why a transfer crawls even when both devices are working perfectly. When you share a file, two connections matter - Your upload speed and the recipient's download speed - And the slower of the two sets the pace. Most home connections upload much slower than they download, which is why sending a file often takes longer than receiving one.
- Bitrate
- Bitrate is how much data is used per second of audio or video, shown in kilobits or megabits per second (kbps/Mbps). A higher bitrate keeps more detail, so the clip looks and sounds better - But the file grows quickly: one minute of 4K video can weigh hundreds of megabytes. Bitrate matters when you share because it decides both the file size and how the clip survives re-compression. Chat apps often re-encode video at a lower bitrate, which is why clips arrive blurry. Sending the original file with a share link skips that re-encoding, so the recipient gets the same bitrate you recorded.
- Cloud storage
- Cloud storage keeps your files on servers you reach over the internet instead of only on your own device. Services like Google Drive and Dropbox let you upload once and open the file from any device, which is ideal for long-term keeping and syncing. Sharing from cloud storage works, but links usually live until you remember to revoke them, and recipients sometimes need an account. That is the key difference from expiring-link tools: cloud storage is built for keeping files, while transfer tools are built for handing them over and cleaning up automatically. Many people use both - The drive for archives, expiring links for handoffs.
- Content-Disposition
- Content-Disposition is an HTTP header a server sends along with a file to tell the browser what to do with it. Set to "attachment," it triggers a download prompt and can suggest the file name to save; set to "inline," it asks the browser to display the file in the page instead - That is how PDFs and images can preview in a tab rather than downloading. File-sharing sites use this header behind the scenes: a preview button serves the same file inline, while the download button serves it as an attachment, so the file lands in your downloads folder with its proper name.
- Download
- Downloading is copying a file from the internet or another device onto your own. When someone opens a share link and saves the file, they are downloading it - The original stays on the server, and the recipient gets their own copy. Speed depends on the file size, the server, and the connection on both ends. On expiring-link services a download can also carry side effects: on ShareIt.onl each download extends the link's life by 24 hours, and a one-time link deletes the files right after the first download completes. That is why "who downloaded, and when" matters more on sharing sites than on the open web.
- Encryption in transit (HTTPS/TLS)
- Encryption in transit scrambles data while it travels between your device and a server so nobody along the way can read it. It is handled by HTTPS and TLS - The padlock icon and the "https" at the start of a web address. Without it, anyone on the same public Wi-Fi could watch your upload go by; with it, your file rides through the network as unreadable ciphertext until it reaches the server. Any file-sharing site you trust should use HTTPS on every page, including the actual upload and download. It protects the journey, not the destination - What happens on the server is a separate question (see end-to-end encryption).
- End-to-end encryption (E2EE)
- End-to-end encryption locks a file so only the sender and the chosen recipient can unlock it. The service in the middle moves sealed boxes but never holds the key, so even its own staff or a hacked server cannot read the contents. That is stronger than encryption in transit, which only protects data while it travels. E2EE matters most for genuinely sensitive material - Contracts, medical records, IDs. The tradeoff is convenience: keys must be exchanged, and features like on-page previews are harder to offer. A practical middle path: encrypt the file locally first (for example an encrypted archive), then share it by an ordinary expiring link.
- exFAT
- exFAT is a file system used to format USB drives and memory cards so both Windows and macOS can read and write them without extra software. Unlike the older FAT32, exFAT supports single files larger than 4 GB - The reason a long 4K video sometimes refuses to copy onto an old stick. That makes exFAT the default choice for moving big files between computers by hand. It is worth knowing whenever you use a drive as the messenger; for anything under a couple hundred megabytes, a browser share link is usually quicker than finding a drive, formatting it correctly, and walking it over.
- Expiring link (link expiry)
- An expiring link is a share link that stops working after a set time. Once the timer runs out, the files behind it are deleted and anyone clicking the old link sees an expired page instead. This is a security feature, not a limitation: links get forwarded, inboxes get breached years later, and a permanent link keeps working for whoever finds it. An expiring link caps that risk mathematically - After the window closes there is nothing left to leak. On ShareIt.onl you pick 1 hour, 12 hours, 24 hours, 3 days, or 7 days at upload, and each download keeps an active link alive for another 24 hours.
- File compression
- File compression shrinks a file by packing its data more efficiently. Smaller files upload faster, download faster, and squeeze under size limits. Lossless compression (ZIP, PNG, FLAC) keeps every bit and restores the original perfectly; lossy compression (JPEG, MP3, most video) throws away detail the eye or ear barely notices to save much more space. Two practical notes for sharing: already-compressed formats like JPEG photos and MP4 video barely shrink when zipped, so zipping them mostly just bundles; and re-compressing a lossy file again and again degrades it - Which is why sending the original with a link beats re-sending screenshots of screenshots.
- HEIC
- HEIC is the image format iPhones use by default to store photos at high quality in roughly half the size of an equivalent JPEG. The space savings are real, but support outside Apple is patchy: older Windows PCs and many web tools cannot open HEIC files without a codec or a conversion step. That surprises people the first time they share iPhone photos - The recipient gets files they cannot open. The options: convert to JPEG before sending, let the iPhone convert on export, or share the original HEIC through a link so the recipient can choose (photographers often want the untouched original).
- Metadata (EXIF)
- Metadata is extra information stored inside a file that describes it - Dates, file type, author, camera settings. For photos this hidden data is called EXIF, and it can include the exact GPS location where the picture was taken, the device model, and the time to the second. That is worth knowing before you share: post a photo taken at home and the coordinates of your house may ride along inside the file. Social networks usually strip EXIF on upload; direct file transfers usually do not, because keeping the original intact is the point. For sensitive photos, strip the metadata first or re-export the image.
- MIME / Base64 encoding
- MIME is the labeling standard that tells software what type a file is - image/jpeg, application/pdf, video/mp4 - So browsers and mail apps know how to handle it. Base64 is a companion trick that converts binary file data into plain text so it can travel through systems designed for text, such as email. The cost is size: Base64 makes a file about a third larger, which is one reason a 20 MB attachment limit really fits a ~15 MB file. Share links sidestep the whole problem - The link is tiny text, and the file itself travels as efficient binary over HTTPS.
- One-time link (burn after reading)
- A one-time link works exactly once: after the first download, the files are deleted and the link goes dead. This is sometimes called "burn after reading." It is the right tool for handing over something you never want fetched twice - A password list, a contract draft, an ID scan. The tradeoff is fragility: if the wrong person clicks first, the content is gone and you will know to re-share. For that reason one-time links pair well with a password, so only the intended person can trigger the single download. On ShareIt.onl it is the "Delete after first download" checkbox under Password & more.
- P2P (peer-to-peer) transfer
- Peer-to-peer transfer sends a file straight from one device to another without parking it on a middle server. Because the data flows directly, P2P can be very fast on a local network and private by design - No copy sits in the cloud. The constraints: both devices generally need to be online at the same time, and firewalls or office routers often block device-to-device connections. Apps like SHAREit, AirDrop, and Quick Share are P2P at heart. Server-based share links flip the tradeoff: sender and recipient never need to be online together, at the cost of the file briefly living on a server.
- Password protection
- Password protection requires the correct password before anyone can open or download a shared file. It defends against the most common leak: a link forwarded, pasted, or found by someone it was never meant for. The link alone becomes useless without the second secret. For it to work, send the password through a different channel than the link - Link by email, password by text message, for example. On ShareIt.onl you can add a password to any share; recipients enter it once and the files unlock for their visit. Combine it with a short expiry and the exposure window for sensitive material shrinks to hours.
- QR code
- A QR code is a square pattern of dots that a phone camera reads as a link. Point the camera, tap the prompt, and the page opens - No typing, no account pairing, no cable. For file sharing, QR codes remove the most awkward step of cross-device transfers: getting a long URL from one screen onto another. Upload on a laptop, scan with the phone, download - Done in seconds, even between platforms that share nothing else. ShareIt.onl shows a QR code next to every share link for exactly this reason. Anyone who can see the code can open the link, so treat a printed QR like the link itself.
- Token (in a URL)
- A token is the long string of random characters inside a share link that identifies one specific share. It works like a key: the server only serves the files when the exact token is presented. Randomness is the security - With billions of possible combinations, guessing a valid token is practically impossible, which is why unlisted links are safe to use without accounts. The flip side: anyone who has the full link has the token, so forwarding the link forwards access. That is why sensitive shares deserve a password or a short expiry on top of the token, and why links are best sent in private channels.
- Upload
- Uploading is copying a file from your device to a server or another device over the internet. It is the first half of every share: your file travels up to the server, then the recipient's download brings it back down. Upload speed is the usual bottleneck - Most home and mobile connections upload several times slower than they download, which is why sending 200 MB takes noticeably longer than receiving it. Modern uploads travel in chunks over HTTPS, so a brief Wi-Fi hiccup resends one chunk instead of restarting the whole file. On ShareIt.onl the share link and QR code appear the moment the upload completes.
- Wi-Fi Direct
- Wi-Fi Direct lets two devices connect over Wi-Fi without a router or internet between them - One device briefly acts as the access point. Because Wi-Fi carries far more data than Bluetooth, it is the muscle behind most nearby-sharing features: AirDrop, Quick Share, and SHAREit all use direct Wi-Fi links to reach their speeds. In practice a Wi-Fi Direct transfer can hit 20+ MB/s, so multi-gigabyte videos move in minutes. Its limits are proximity and pairing quirks between brands. Beyond arm's reach - Or between platforms that refuse to pair - Internet share links take over.
- ZIP archive
- A ZIP archive packs many files and folders into one file, usually with compression. For sharing, that solves two problems at once: you send a single download instead of twenty attachments, and the folder structure survives the trip intact. The recipient unzips and gets everything back in place - Windows, macOS, and modern phones can all open ZIPs natively. Two notes worth knowing: photos and videos barely shrink because they are already compressed, and some email services block encrypted ZIPs because they cannot scan them. On ShareIt.onl you can upload files individually (up to 10 per share) or zip a bigger folder into one upload.
Put it into practice
Ready to try it? Share files free with an expiring link and QR code, or read the full guides.
Tools that use these ideas
Every tool below creates an expiring share link with a QR code - No account needed.